Innovative Technique for Seismic Upgrade of RC Square Columns


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Title: Innovative Technique for Seismic Upgrade of RC Square Columns

Author(s): A. Prota, G. Manfredi, A. Balsamo, A. Nanni, and E. Cosenza

Publication: Special Publication

Volume: 230


Appears on pages(s): 1289-1304

Keywords: column; ductility; FRP; smooth bars; strength hierarchy

Date: 10/1/2005

The preliminary results of an experimental investigation on under-designedRC square columns are presented in the paper. The seismic upgrade was achieved bycombining steel spikes and GFRP laminates. Two parameters are investigated: the lapsplice of the longitudinal steel reinforcement and the level of axial load. A comparisonbetween as-built and strengthened columns is presented in terms of strength andductility. The shear-top displacement relationships of strengthened columns areanalyzed to assess the influence on the global performance of the lap splice. Thispreliminary analysis confirms that the proposed solution for the seismic strengtheningof under-designed columns is very effective when it is necessary to relocalize thepotential plastic hinges of columns by increasing their flexural strength. The obtainedresults will represent the basis for developing design criteria for the strengthening ofsimilar interventions and will represent a reference for the calibration of a model of thestrengthened column.